Room-temperature superconductivity?

[tomclarke]

So how the HELL can the Doppler shift change the period of regular pulses coming from their light sources?

It does not change the transmitted frequency, it changes the received frequency. Just as the received frequecy of waves is also changed.

Or, don't think, if that is difficult, see what UG MIT courses say about pulsar astronony:

http://www.youtube.com/watch?v=5wM-5gPHDM4

Topics covered: Doppler Effect, Binary Stars, Neutron Stars and Black Holes. Doppler shift is introduced with sound waves, then extended to electromagnetic waves (radiation). The Doppler shift of stellar spectral lines and/or pulsar frequencies provides a measure of the line-of-sight (so-called radial) velocity of the source relative to the observer. Combined with Newton's law of universal gravitation, this can lead to the orbital parameters and the mass of both stars in a binary star system.

What are you trying to say in your usual foggy manner? This has NOTHING to do with the argument we are having. Have you REALLY studied physics, where, and who were your mentors?

The lecture summary states (as most know anyway) that pulsar frequencies (e.g. frequency of pulses from pulsars) change with relative velocity just as do the e-m frequencies in the pulses.

I studied theoretical physics at DAMTP, Cambridge, UK. Can't remember who were the lecturers, I guess Hawking might have been one...

You surprise me sometimes Johan.

[johanfprins]

It is true that time dilation is difficult to measure directly between two frames with uniform velocity. However even in this case it is the (real) difference in time on the moving clock for a given fixed clock time in the stationary frame.

It cannot be the REAL difference in time (delta)ts on the moving clock, but the TRANSFORMED time (delat)t which is NOT the real difference in time on the moving clock.

Thus. Set up clocks throughout space in the stationary frame to be synchronised. (True, you use e-m rays to do this). Using these clocks, which whizz by, you can compare the moving clock with the stationary frame time.

OK: When you synchronise any one of your stationary clocks with the moving clock when it passes that stationary moving clock there will be
NO TIME DILATION between your stationary clock and the clock moving past.

Time dilation says that when 1s has elapsed on the moving clock the whizzing by stationary clocks will register more than 1s elapsed.

No it does not. The Lorentz transformation states very clearly that when you synchronise one of your clocks with the moving clock at time ts, there will be NO time dilation between these clocks at all; and also not between the clock moving past and all your other stationary clocks which are ticking away in synchronisation with one another.

The time dilation is easily seen without extra clocks by making the moving clock return and comparing times, as in the twins paradox.

This is your usual nonsense which violates Einstein's first postulate.

[johanfprins]

Perhaps your grandson aged 4 does not yet understand relativistic physics?

Thank God for that. And thank God he did not learn it from your mentors. He is still sound of mind to think logically.

And you are here making the mistake I highlighted above - assuming some frame-independent measure of instantaneity for events spatially separated.

This is demanded by Einstein's first postulate which you just willy-nilly wipe under the carpet.

[johanfprins]

.

See above to Walter Lewi's MIT basic astronomy lecture on pulsars, where the pulsar motion relative to earth can be detected as a pulse frequency change.

Of course you can do this but this has NOTHING to do with the twins paradox which we are discussing. Stop insulting MIT.

You surprise me sometimes Johan.

Why do you not surprise me by trying to think logically for a change: A person who claims that two clocks moving away from, and then again towards one another while keeping the exact same time rate and synchronised time within their respective inertial reference frames, will show different times when the meet up again, must have a serious problem with logic.

Good night.

[johanfprins]

http://en.wikipedia.org/wiki/Hafele%E2% ... experiment

It appears the experiment was done and not just done, but repeated with a precision within 1%.

Experiments conducted: 1971, 1976, 1996, and more with increasing precision.

The clocks were NOT flown through space without any change in gravity. So the experiment required was not done and must still be done sometime in future.

[tomclarke]

.

See above to Walter Lewi's MIT basic astronomy lecture on pulsars, where the pulsar motion relative to earth can be detected as a pulse frequency change.

Of course you can do this but this has NOTHING to do with the twins paradox which we are discussing. Stop insulting MIT.

You surprise me sometimes Johan.

Why do you not surprise me by trying to think logically for a change: A person who claims that two clocks moving away from, and then again towards one another while keeping the exact same time rate and synchronised time within their respective inertial reference frames, will show different times when the meet up again, must have a serious problem with logic.

Good night.

Johan:
Please refer back to my post above - I've explained in more detail why Lewi's lecture is relevant to your objection. You will remember you disagreed with my statement that received pulses would be lower pulse frequency due to doppler effect. He agrees with me, not you, who claim received and transmitted pulses must have same frequency.

[johanfprins]

I did the calculation. The result is that the observers disagree on the amount of time which elapsed during the journey, which is consistent with the travelling person experiencing a shortening of the distance during travel.

Then you have done the calculation incorrectly: Paste you calculation, which must be quite a number of pages long if you did the calculation correctly, and I will show you where you have gone wrong.

[johanfprins]

Johan:
Please refer back to my post above - I've explained in more detail why Lewi's lecture is relevant to your objection. You will remember you disagreed with my statement that received pulses would be lower pulse frequency due to doppler effect.

I most certainly DID NOT. Why do you lie? I stated that if you do the full calculation, which you are obviously not able to do, you will see that the terms relating to the Doppler shift DOES NOT change my conclusion.

Please do not distort what I am saying: This is the worst method of lying EVER.

So now DEFINITELY: Good Night.

[tomclarke]

I did the calculation. The result is that the observers disagree on the amount of time which elapsed during the journey, which is consistent with the travelling person experiencing a shortening of the distance during travel.

Then you have done the calculation incorrectly: Paste you calculation, which must be quite a number of pages long if you did the calculation correctly, and I will show you where you have gone wrong.

Johan,

I don't think you should try to correct anything till you have attended Walter Lewi's youtube lecture and corrected your misapprehension about Doppler shift!

[johanfprins]

Johan,

I don't think you should try to correct anything till you have attended Walter Lewi's youtube lecture and corrected your misapprehension about Doppler shift!

It did not help you out of your stupor: So why should I "attend" this lecture when I can deliver a better lecture on the Doppler effect than Walter Lewi can ever hope to do.

[ladajo]

http://en.wikipedia.org/wiki/Hafele%E2% ... experiment

It appears the experiment was done and not just done, but repeated with a precision within 1%.

Experiments conducted: 1971, 1976, 1996, and more with increasing precision.

The clocks were NOT flown through space without any change in gravity. So the experiment required was not done and must still be done sometime in future.

If they only use the data from when the aircraft are at altitude, how does the gravity change (other than the normal differences found on the planet from point to point)?

Conceptually, Johan, I think the test you are arguing for is the comparison of a GEO based clock against a surface clock. Although I will have to think a moment about how they adjust for Earth Centered.
But, in the proposed setup, neither clock is moved once on station. Thus both have no change in gravity (other than the GEO clock moving closer and farther from the sun than the surface clock does as it orbits). The surface clock is moving at earth surface speed as the earth turns, covering the 25K miles around the equator at about 0.289 miles per sec. The GEO bird is moving at its orbit speed to hold station with the surface clock, covering 165K miles on each rotation at about 1.91 miles/sec. So from an Earth centered frame, they are moving at different speeds, and thus would incur an SR difference?

Curt Renshaw argues that the effects seen are based on the rotational aspect of the motion, and that is is essentially equal to an accelleration (like gravity). He points to the spinning disk clock experiments that induce clock error with high speed centrifuge type set ups.
He also points out that the Keating experiment was done only as an after the fact comparison of clock data, vice monitering while in flight, and also was corrected to Earth Centered.

http://renshaw.teleinc.com/papers/london1/london1.stm

I also liked this article: Optical Clocks and Relativity
Found here:
http://tf.boulder.nist.gov/general/pdf/2447.pdf
where they explore relativistic issues using optical clocks.

I also found this one interesting (older article) where the author discusses issues regarding the reformulation of relativistic transformation between coordinate time and atomic time:

http://ipnpr.jpl.nasa.gov/progress_repo ... 21/21E.PDF

[tomclarke]

Johan,

I don't think you should try to correct anything till you have attended Walter Lewi's youtube lecture and corrected your misapprehension about Doppler shift!

It did not help you out of your stupor: So why should I "attend" this lecture when I can deliver a better lecture on the Doppler effect than Walter Lewi can ever hope to do.

Now who is disrespecting MIT?

But Johan, don't you feel this wholesale denial of standard physics because it does not fit your preconceptions is unbecoming?

Why not take a deep breath and admit that Doppler effect does exist, and means that the received frequency of waves (& pulses) differs from transmitted when there is relative velocity between transmitter and receiver. You cannot hide from this one, and I guess 90% of readers here know you are wrong without needing a lecture from MIT.

Best wishes, Tom

[ladajo]

And I really found this paper to be the best write up I have yet seen on GPS relativistic correction:

http://tycho.usno.navy.mil/ptti/1996/Vol%2028_16.pdf

[ScottL]

http://en.wikipedia.org/wiki/Hafele%E2% ... experiment

It appears the experiment was done and not just done, but repeated with a precision within 1%.

Experiments conducted: 1971, 1976, 1996, and more with increasing precision.

The clocks were NOT flown through space without any change in gravity. So the experiment required was not done and must still be done sometime in future.

That doesn't seem right. From what I understand, we're suggesting that we merely increase the radius of the orbit of the clock around the Earth. How does this provide a better experiment? Other than reducing but not eliminating the effect of gravitational force from the Earth on the moving clock, what purpose was served?

I'm trying to get a better understand to please don't view this as an attack.

[Teahive]

Johan,

again, could you please explain which two quantities the "time rate" you are talking about is a quotient of? Without an unambiguous definition any statement using it will not be unambiguous, either.

I did the calculation. The result is that the observers disagree on the amount of time which elapsed during the journey, which is consistent with the travelling person experiencing a shortening of the distance during travel.

Then you have done the calculation incorrectly: Paste you calculation, which must be quite a number of pages long if you did the calculation correctly, and I will show you where you have gone wrong.

The calculation is actually very simple, and it's already in this thread:
viewtopic.php?t=2137&start=1610